Proper alignment of vehicle wheels is well recognized as being important to safe operation and correct performance according to the makers specification. Heretofore, means to determine wheel alignment has included mechanical tie-in between steerable wheels with read-out dial means or with electrically responsive signalling devices such as lights or buzzers. In some instances visual sighting means has been related with the vehicle wheels to determine limited alignment characteristics.
The problems with such prior means has been that it is difficult for service operators to obtain readings in a short time for what can be a relatively simple operation. Other problems have existed, such as the high cost of alignment determining apparatus, apparatus that can easily be misused or does not retain the original accuracy, or apparatus that is difficult to use because of the way it must be installed and operated. Some prior devices are incapable of determining certain wheel alignment characteristics that are important to overall alignment determination and correction.
It is evident that in some instances vehicles are assembled in haste which can result in alignment errors, or are not always checked to determine whether the wheel alignment geometry is correct or within acceptable tolerances. Vehicles with wheels out of alignment can be spotted while in motion by noting whether the front and rear wheel track. Improper wheel toe is not as easily visually noted, but can be found by noting tire wear and handling response.